A Native American grinding stone was a tool used to grind various foods, such as corn or acorns, to prepare them for cooking. The stones were part of a two-piece tool set consisting of a mano and a metate.
The large stone metate had a bowl-like hollow that held food. The mano was held and used to grind the food against the hard surface of the metate. The resulting grounds had a mealy texture.
Some Native American tribes would use a large, communal rock for grinding, and the women of the tribe would gather to socialize while working. An example of this occurrence is the California Indian Grinding Rock in Capitol Park.